1. Field of the Invention
This invention relates generally to the synthesis of speech waveforms having a smoothed delivery.
2. Related Art
One method of synthesising speech involves the concatenation of small units of speech in the time domain. Thus representations of speech waveform may be stored, and small units such as phonemes, diphones or triphones--i.e. units of less than a word--selected according to the speech that is to be synthesised, and concatenated. Following concatenation, known techniques may be employed to adjust the composite waveform to ensure continuity of pitch and signal phase. However, another factor affecting the perceived quality of the resulting synthesised speech is the amplitude of the units; preprocessing of the waveforms--i.e. adjustment of amplitude prior to storage--is not found to solve this problem, inter alia because the length of the units extracted from the stored data may vary.